1. Field of the Invention
The invention relates to a machine for the manufacture of a fiber material web, in particular a tissue paper or hygienic paper web, having at least one pressing gap (nip) which is formed between a shoe pressing unit and a drying or tissue cylinder, and water absorbent carrier band, a water-impermeable pressing band and the fiber material web guided through the at least one gap. It also relates to a method for the manufacture of a fiber material web, e.g., a tissue or hygienic paper web, in which the fiber material web to be dewatered is passed together with a carrier band through a pressing gap (nip).
2. Discussion of Background Information
A plurality of embodiments of a machine of the initially named kind are described in DE-A-42 24 730. In this document, at least two pressing gaps are in each case provided in all embodiments. The main press, which lies to the rear when viewed in the direction of travel of the web, includes in each case a drying cylinder and an associated pressing element. A suction pressing roller or a shoe pressing roller can be provided as a pressing element of this kind.
Two pressing gaps are again also provided in a machine of the initially named kind which is known from DE-A-196 54 197. The rearwardly lying main press is formed by a shoe pressing unit and a drying cylinder.
Thus, in the known machines two or more pressing gaps are always provided. This is considered to be imperative in order to achieve on the one hand a careful dewatering without a squashing, which is demanded in particular in the manufacture of a tissue paper or hygienic paper web, and on the other hand an improved production performance through an increased dry content after the press. In this a careful dewatering of the web without a squashing is achieved with the complete or partial replacing of the roller gap presses by shoe presses as a result of the corresponding gap lengthening or the increase in the pressing time respectively.
A substantial disadvantage of known embodiments includes the relatively high investment and operating costs in comparison with the improvements achieved. In view of the previously usual limiting of the maximum line force to a value in the region of 90 kN e.g. for Yankee cylinders it was always necessary in the known press designs to provide at least two pressing gaps.